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RESEARCH - PHOSPHORUS – BMPs
Best Management Practices (BMPs) are effective, practical, structural or nonstructural methods which prevent or reduce the movement of sediment, nutrients, pesticides, and other pollutants from the land to surface or ground water, or which otherwise protect water quality from potential adverse effects of agricultural activities. These practices are developed to achieve a balance between water quality protection and agricultural production within natural and economic limitations. BMPs for phosphorus (P) include on-field improvements, and edge-of-the-field sinks. An essential element of BMP research includes BMP monitoring and effectiveness. This website highlights some of the efforts to develop and improve BMPs for P within the Land Grant University System, often with CSREES funding.
On-field improvements
Researchers are evaluating the performance of various on-field BMPs aimed at minimizing P loss, often in overland runoff, from the field.
Researchers
at the University of Nebraska found that no-till
systems reduced sediment and nutrient yield during intense rainfall
and that terracing is effective in meeting the sediment yield target, 
but
compaction should be avoided to reduce runoff and dissolved nutrient
losses.
Researchers at the University of Mississippi found that using multiple inlet plus intermittent rice irrigation, producers were able to capture more rainfall and reduce irrigation inputs by 30% 
as compared to continuously-flooded rice fields thereby reducing the potential for non-point source runoff of agrochemicals from rice fields.
Downstream of a Tailwater
Recovery System (a
planned irrigation system in which all facilities utilized for
the collection, storage, and transportation of irrigation tailwater
for reuse have been installed) with a bioretention pond component,
Total P load decreased by 25%, according to research at Rutgers
University.
Researchers at the University of Maryland are describing soil
profiles, flowpaths, and P losses of agricultural drainage ditches. They
propose the installation
of P-sorbing materials in flow control structures to minimize soluble
P losses .
Research conducted with producer collaborators in North and South Dakota indicate that remote sensing and targeted scouting and soil sampling can be used to reduce the real risk associated with adopting BMP’s.
University of Wisconsin’s Discovery Farms Program is evaluating the impact of agriculture on the quality of surface water runoff by monitoring edge-of-field sites on privately owned farms throughout Wisconsin. They have concluded that on-farm management of manure application during the period that the ground is frozen is critical to the loss of P.
At the University of Wisconsin, dissolved
reactive phosphorus (DRP) leaching losses were
higher from the managed, fertilized agroecosystems compared to
the natural, restored prairie. However, despite higher drainage
from the fertilized chisel-plowed agroecosystem, the no-tillage
agroecosystem consistently maintained higher DRP concentrations
in soil leachate solutions at 1.4 m below the soil surface, which
led to higher DRP leaching losses for the fertilized no-tillage
agroecosystem.
The Clear Creek Buffer Project at the University of Nebraska demonstrated that on a watershed scale, grassed buffers, riparian forest buffers, and other conservation practices applied on the same watershed can reduce total phosphorus loads to an ephemeral stream by 95 %.
Iowa State University researchers have demonstrated that riparian buffers re-established on previously cropped or pastured land have tremendous potential to remediate nonpoint source pollution in agricultural watersheds. – P losses were reduced by 80%. Insights from this study 
are being used to improve buffer performance and placement within watersheds.
Researchers at Colorado State University evaluated the feasibility of using bank stabilization structures that are modified to include a permeable reactive barrier to reduce phosphate in groundwater and surface water runoff before contamination of streams can occur. The results indicated that reactive stream stabilization structures with sawdust can remove significant amounts of phosphate, removal ranged from 78-95%. These results will provide guidance for design of stream restoration projects.
BMP monitoring and effectiveness at the watershed scale
Monitoring of water quality throughout a watershed enables researchers to assess the effectiveness of multiple implemented BMPs.
Kansas State University researchers are monitoring the water quality for a paired-watershed study of targeting BMP adoption to the most critical areas of a watershed. In three watersheds, targeted BMP adoption is occurring while in two adjacent watersheds, there is no BMP incentives program.
The Wisconsin Discovery Farms and Water Action Volunteers (an extension volunteer water quality monitoring program) joined forces to work with privately owned farms to identify effective and economical BMPs and to monitor and learn how these BMPs are improving water quality.
Researchers at the University of West Florida are studying the efficacy of BMPs on runoff water quality from row-cropping, silviculture and aquaculture discharge at the field and watershed scale. Results of this project were combined with education and extension activities to disseminate information to the public and encourage BMP implementation.
University of Arkansas researchers are synthesizing historic watershed BMP, land use, and water quality data in a GIS-linked database to quantify the impact of BMPs on water quality.
Visit the Watershed Management Research page to learn more about Evaluating BMPs at the Watershed Scale.
page last modified on
May 21, 2008
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